Double Buffers

To improve throughput, Symbian platform provides the double buffer mechanism. This is a feature that allows a block of data to be prepared by the media driver while the hardware transfers a block of data. DMA transfers data without interrupting the CPU.

The MultiMediaCard subsystem performs multiple data transfers in a single bus transaction.

If your implementation uses double buffers, you must set the ESupportsDoubleBuffering flag into the TMMCMachineInfoV4::iFlags data member in your implementation of DMMCStack::MachineInfo(). This flag causes the platform independent layer to provide the support you need.

If your MultiMediaCard controller uses DMA and your platform specific layer supports physical addresses, you must use double buffers.

See also:

• MachineInfo()

• Implement double buffers